This invention relates to a device for detecting angular accelerations and decelerations of a vehicle road wheel and, more specifically, to such a device particularly suitable for use with vehicle anti-skid brake control apparatus.
The primary object of the present invention is to provide a novel device of the kind as described above which is capable of the most accurate detection of an angular wheel acceleration and deceleration exceeding a prescribed level during a substantially extended service life without employing any mutually contacting elements.
According to the present invention, there is provided a device for detecting angular accelerations and decelerations of a vehicle road wheel comprising a first shutter member of cylindrical shape secured coaxially to a rotating member of a vehicle, which rotates with said vehicle road wheel, and having a cylindrical side wall formed therethrough with a plurality of circumferentially equispaced light-beam passage holes, a sensor weight mounted on said rotating member through a damping means for limited angular displacement relative thereto, a second shutter member of cylindrical shape secured to said weight in coaxial relation with said first shutter member, said second shutter member having a cylindrical side wall formed therethrough with a plurality of light-beam passage holes corresponding to said first-mentioned holes in said first shutter member, said last-mentioned holes being circumferentially equispaced at the same interval as that of said first-mentioned holes and arranged normally out of registry therewith, a pair of light-beam emitting and receiving means fixedly mounted on a non-rotating member of the vehicle in radially aligned, spaced and opposite relation to each other with said first and second shutter members interposed therebetween, wherein when said sensor weight is caused, due to an angular acceleration or deceleration of said wheel exceeding a prescribed value, to rotate relative to said rotating member at a predetermined certain angle of rotation, said light-beam passage holes in said first and second shutter members are placed into registry with each other so that said light-beam receiving means receives light beams emitted from said light-beam emitting means to produce a desired output signal.
The above and other objects, features and advantages of the present invention will be more fully understood from the following detailed description of the invention, when read in conjunction with the accompanying drawings, which illustrate one exemplary, presently preferred embodiment of the invention.